What's the difference between nucule and nutlet?

Nucule

Definition:

Example Sentences:

Nutlet

Definition:

• (n.) A small nut; also, the stone of a drupe.

Example Sentences:

• (1) Evidently, in their search for food, the ancient people found that the four nutlets contained in the dry and spinose calyx of the Chinese motherwort resemble the seasame seed in size and oil content.